Methods related to making decorative glass windows

ABSTRACT

A decorative window consists of thick transparent plastic resin layer laminated to a sheet of glass. The outer surface of resin layer includes decorative features, such as deeply contoured pictographic images and finely detailed textured surfaces. The decorative window is produced as replica of a glass master originally made using conventional grinding and surfaces finishing techniques. The master is then covered with a mixture of silicone, catalysts for curing the silicone, and a light oil to form a mold. After curing, the mold is removed from the glass master, inverted and a glass sheet, which has been prepared for the process by being coated with organosilane ester, is clamped thereto. The mold cavity is then filled with a mixture of a clear plastic resin, catalysts for curing the resin, and organosilane ester. After curing, the replicated decorative window is removed from the mold.

This application is a divisional of application Ser. No. 08/573,764, nowU.S. Pat. No. 5,783,264, filed Dec. 18, 1995 which is a continuation ofapplication Ser. No. 07/807,236 filed Dec. 16, 1991 (now abandoned).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to decorative windows, and, morespecifically, to windows having the appearance of textured and deeplycontoured glass and to a method of making such windows.

2. Background Information

Decorative windows composed of contoured and textured glass have beenmade for many generations, reaching a peak in popularity asarchitectural elements in the last century. Such windows are currentlyenjoying a revival in popularity, being used particularly as centralelements in front doors and as adjacent elements above and beside suchdoors. Such windows are also being used increasingly in commercialapplications for decorative purposes and to form portions of partitions.

In the traditional process, such windows are made from relatively thickplate glass, having various sorts of grooves and other contours groundtherein and polished to restore smooth surfaces with desirable opticalproperties. Certain portions of glass surfaces are textured using sandblasting, acid etching, or a process called "glue chipping" in which anadhesive applied to a sand blasted surface is stripped to leave aspecific pattern. Such windows can also be made as composites of anumber of glass panels having deeply beveled edges joined by lead stripscontoured for this purpose.

A principle disadvantage of windows of this kind is their cost. A windowof moderate size and complexity can easily cost over one thousanddollars, due particularly to the large amount of skilled labor necessaryin its production. Furthermore, windows of this type have disadvantagesassociated with the mechanical and thermal properties of glass. Theeffects of the low impact resistance of glass are often accentuated bydeep cuts with sharp internal corners made in the application of adecorative design, and the transfer of heat between the interior andexterior regions of a building through glass panes increases heating andair conditioning costs. Also, decorative windows made as composites ofvarious glass panels cannot be used in many architectural applicationsbecause building codes require the use of safety glass windows in entrydoors and load bearing walls.

DESCRIPTION OF THE PRIOR ART

A number of attempts have been made to simulate traditional decorativewindows using various manufacturing processes having lower associatedcosts. For example, windows with decorative designs and surfaces havebeen injection molded using clear thermoplastic materials, such ascertain types of polycarbonate. However, injection molding has a seriousdisadvantage in the high cost of the tooling required. The high cost ofthe dies required in this application is particularly significant, sincesuppliers of such types of windows and associated architectural elementsgenerally need to have an inventory including a large number of windowsizes and design patterns. Further, injection molded thermoplasticwindows have not generally met with commercial success as finearchitectural elements, because they do not look and feel like realglass. Rather, thermoplastic windows are much too flexible compared toglass and transmit and reflect light differently than real glass. Inaddition, limitations in the ability of the die casting process toproduce certain features, such as sharp internal and external edges,detract from the appearance of plastic substitutes for decorative glasspanels.

A method for making a solid, continuous plastic part with a texturedsurface simulating stained glass is described in U.S. Pat. No.3,848,046, issued to M. W. Machet on Nov. 12, 1974. In accordance withthis method, a mold is first made by pouring a gel substance, such asstandard clear gelatin in an aqueous liquid form, into a mold surface toform a gel layer. Before this layer hardens, an absorbent, such as drypowdered gelatin, is sprinkled on its surface. This powder absorbsmoisture, swells, and merges into the gel surface while causingshrinkage of the surface, forming a nodular surface texture. After thegelatin has hardened, a stained glass simulating material, such aspolyester resin prepared in a liquid form with a catalyst added, ispoured on the textured surface. After the resin hardens, the gelatinmold is dissolved in water and washed off the resin part, which is leftas a finished article. In a modification of this process, a hardenedplastic framework, including a number of openings, is dropped into thegelatin after the absorbent is added but before the gelatin hardens.Textured resin material is thus allowed to harden in the openings withinthe framework, simulating a window with multiple panes. While thegelatin mold produced in this process is certainly less expensive thanthe steel molds required for use in the injection molding process, it isonly capable of producing a single finished article. Also, this processproduces only a random nodular surface texture; it does not producepictorial, sculptured designs within the surface of the finishedarticle.

U.S. Pat. No. 3,546,051, issued to R. Utz on Dec. 8, 1970, describes amethod for simulating the overall appearance of a stained glass windowby providing a glass pane behind an injection molded plastic frameworkincluding a pattern of ribs forming pictorial fields. Various pictorialfields in the pane are colored using stencils. The framework ismetallized by the application of metal foil under heat and pressure, byvacuum deposition, or by spraying. While this patent is directed atmaking a realistic framework, nothing is done about the glass except forcoloring.

Methods for making simulations of decorative glass windows usingthermoplastic films and thin layers of resins adhered to glass paneshave been described in a number of U.S. Patents. For example, U.S. Pat.No. 3,713,958, issued to R. S. McCracken on Jan. 30, 1973, describes astructure in which a coating of a substantially clear resin, such as anepoxy, vinyl, acrylic, or polyester type, is applied to one side of aglass pane, while light-transmissive glass tint is applied to theopposite side to simulate stained (colored) glass. For the resin, acopolymer of N-butyl methacrylate and methyl methacrylate in aromaticsolvents was found to be compatible with glass.

U.S. Pat. No. 4,335,170, issued to D. Butler on Jun. 15, 1982, describesa method of simulating stained and leaded glass windows in which a verythin polyester film is attached to a sheet of glass using an adhesive.Individual film segments are cut to correspond with design segmentshaving different colors. After the adhesive is applied to the film, asoap solution is applied thereon to neutralize the effect of theadhesive during the process of positioning the film on the glass. Afterthe film is positioned on the glass, the soap solution is forced outwardby pressure with a squeegee so that adhesion occurs.

U.S. Pat. No. 4,791,010, issued to P. A. Hanley et al. on Dec. 13, 1988,describes the application of a unique liquid mixture of ink and varnishto a glass pane in order to produce a simulated etched glass appearance.A framework of spacers is then placed atop the glass, adjacent to itsedges, surrounding the ink and varnish image, and another glass pane isplaced atop the spacers. These items are then formed into a permanentassembly, with the image protected on the inside surface of the firstglass pane, as a sealing materials are applied around outer surfaces ofthe spacers.

U.S. Pat. No. 4,154,880, issued to F. E. Drennan on May 15, 1979,describes a window pane with a decorative molding on a side, attached byan adhesive strip. The molding includes flanges which mechanically lockwith the adhesive strip. This patent indicates that areas of the glassadjacent to the molding sections can be of different colors or can havedifferent surface treatments, such as sandblasting.

The methods described in the above paragraph have the disadvantage ofproviding only very thin coatings on the glass surfaces. While U.S. Pat.No. 3,713,958 to McCracken describes the texturing of the resin with arod or other tool to provide an irregular or wavy surface as produced bymedieval methods of making glass, none of these approaches are capableof providing the deeply contoured or sculptured appearance, includingrecognizable pictorial elements, associated with many decorativewindows. Furthermore, none of these techniques can provide the widevariety of surface finishes associated with decorative glass at areasonable cost.

A method for making a different sort of decorative panel is proposed inU.S. Pat. No. 3,516,893, which was issued to A. J. Gerard on Jun. 23,1970. A printed acetate fabric, having a colored design, is adhesivelyattached on one side to a sheet of tempered glass and on the oppositeside to a backing sheet, which is preferably methacrylate ester polymer.The adhesive is of a type, such as a mixture of acetone and butylacetate, which totally or partially dissolves the acetate fibers of thefabric without destroying the color and pattern of the printed design.After the adhesive is cured, the tempered glass is shattered, creating amosaic effect while retaining its panel form.

A number of patents describe methods for the simulation of multi-panewindows in structures having a continuous pane of glass to which otherelements of substantial thickness are attached. For example, U.S. Pat.No. 4,495,739, issued to F. E. Drennan on Jan. 29, 1985, and U.S. Pat.No. 4,518,446, issued to F. E. Drennan on May 21, 1985, describe adecorative window and a method for manufacturing, wherein ornamentallead strips are attached around the edges of one or more glass segmentshaving an edge thickness of about one eighth of an inch, where eachglass segment is bonded to an underlying glass pane, and where the stripis held in place by a polysulfide adhesive carried in its channel andmechanically locked by inwardly directed flanges at its edges. U.S. Pat.No. 4,904,513, issued to E. De Nicolo on Feb. 27, 1990, describes aplurality of plates with beveled edges being adhesively attached to asingle backing pane of glass, preferably through the use of a layer ofpolyvinyl butyrate under conditions of heat and pressure. In onevariation, decorative strips are also glued in place between the beveledplates.

Some prior art patents describe either modifying a single glass pane tolook like a multi-pane window, or alternately and additionally,attaching one or more additional pieces of glass to a backing pane. Forexample, U.S. Pat. No. 4,488,919, issued to D. R. Butler on Dec. 18,1984, describes methods for making a simulated multi-pane beveled andleaded glass window by forming beveled groves to subdivide a glass orplastic plate, with smooth surfaces on both sides, into design segmentsof unrelieved panels. Lead strips are subsequently attached to the flatbottom walls of these grooves, which are preferably formed by machining.In an alternate method, the panel can be formed by injection molding. Inan alternative construction, segments having a substantial thickness,such as sheets of glass, polycarbonate, or poly(methylacrylate) up toabout one quarter inch in thickness, may be laminated to a base pane.

Certain design segments can be provided with a jeweled glass appearanceby securing transparent shapes, having flat inner surface and facetedorsmoothly curved outer surfaces, in place using a pressure-sensitiveadhesive. U.S. Pat. No. 4,619,850, issued to T. J. Charlton on Oct. 28,1986, describes the attachment of a die cast lead component to each sideof a sheet of glass, thereby simulating lead strips holding individualpieces of glass. Surface treatments, such as coloring, sand blasting, or"glue chipping" conventionally applied to decorative glass windows maybe applied if desired to various zones of the glass. In a modifiedversion, a beveled glass layer is adhesively bonded to a zone within thelead components.

One method of replicating an article is to form a mold over the surfaceof an original article using silicone. Then, the formed mold is thenfilled with a resin, which is allowed to cure within the mold before itis removed as a replica. Traditional mold release agents, such as Teflonor silicone, have been sprayed on solid surfaces, to prevent adhesionbetween the mold material and the cured resin replica articles. Suchagents have also been used to facilitate the removal of molds pouredaround original objects. The mild release agents are applied to thesurface of the original object before the mold is made, or to the molditself before the addition of material to be molded into a replica.

The removal of a silicone mold from a glass master posed particularproblems. The adhesive forces between the silicone and the glass were sogreat that as few as one in twenty molds were successfully removed fromthe masters without serious damage using conventional prior art moldrelease agents. Furthermore, the use of traditional mold release agents,applied to the master before pouring the mold, rendered the moldunacceptable for producing replicas of adequate quality since the agentsleft impressions in the mold which were subsequently transferred to thereplicas as roughened surfaces. Due to the intended use of replicas totransmit light and to produce aesthetic effects similar to thoseproduced by cut and polished glass surfaces, the production of plasticdecorative glass replicas is much more sensitive to blemishes than isthe production of virtually all other plastic parts by moldingprocesses.

One potential solution to the prior art problems of using the decorativeglass replica in architectural applications, such as doors and windows,is forming the plastic decorative layer on a conventional glass pane,which then acts as a backing for the decorative plastic layer. Atechnical problem still requiring resolution is the adhesion between acured resin plastic layer and the glass pane used as the backing plate.Excellent adhesion is required, so that the resulting decorative windowscan be used in exterior architectural applications without delaminationoccurring due to large amount of thermal expansion which occurs betweenhot summer days and cold winter nights.

SUMMARY OF THE INVENTION

In accordance with one aspect of this invention, there is provided adecorative transparent member including a flat sheet of glass and acured transparent layer of plastic resin of substantial thicknesslaminated to the flat sheet of glass. The layer of plastic resin extendsas a single continuous layer to a border area around a periphery of thefirst sheet of glass. The layer of plastic resin has a flat innersurface and an outer surface including deeply contoured pictographicfeatures.

In accordance with another aspect of this invention, there is provided aprocess of preparing a decorative transparent member having a curedresin layer adhered to a glass sheet with a decorative design formed inthe cured resin layer and remote from the sheet. The process includesthe steps of coating the glass sheet with an adherent material andclamping a mold to the glass sheet. The mold has a flat peripheralregion and a cavity extending inward within the peripheral region, theperipheral region being in contact with a the glass sheet. In addition,the process includes filling the internal cavity with a catalyzedtransparent plastic resin including the adherent material and allowingthe resin to cure within the internal cavity. Finally, the processincludes removing the mold from the cured resin and adhered glass sheet.

In accordance with yet another aspect of this invention, there isprovided a method for making a mold of a glass master for subsequent usein fabricating replicas of the master. The method includes the steps ofproviding a surrounding framework of upstanding walls spaced apart fromthe glass master and preparing a catalyzed silicone mixture by mixingsilicone, a catalyst, and a light oil. The method then includes pouringthe mixture into the mold producing cavity atop the glass master in aregion defined by the upstanding walls, allowing the catalyzed siliconemixture to cure within the mold producing cavity and removing the moldfrom the mold producing cavity.

In accordance with still another aspect of this invention, there isprovided a mixture for use as a mold of a glass master for permittingreplication of the glass master. The mixture consists essentially ofsilicone, a catalytic mixture to promote curing of the silicone, and alight oil.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of theinvention, reference should be made to the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective, partly cross-sectional view of a decorativewindow in which a resin layer including a deeply contoured surface islaminated to a sheet of glass.

FIG. 2 is a cross-sectional elevation of a glass master prepared inaccordance with the process of this invention for making replicas.

FIG. 3 is a cross-sectional elevation of a mold being prepared formaking replicas of the glass master shown in FIG. 2.

FIG. 4 is a cross-section a l elevation of the mold shown in preparationin FIG. 3 being filled with resin material to form a replica of theglass master shown in FIG. 2.

FIG. 5 is a partial cross-sectional elevation of an alternate embodimentof the invention, in which a second sheet of glass is supported abovethe resin section in a spaced-apart relationship.

FIG. 6 is a partial cross-sectional elevation of a second alternateembodiment of the invention, in which sheets of glass are supported inspaced-apart relationships on either side of the sheet of glass to whicha resin layer is laminated.

DETAILED DESCRIPTION

Referring to FIG. 1, a decorative window 2, includes a glass sheet 4onto which a plastic resin layer 6 is laminated. Laminated layer 6,which is preferably composed primarily of a clear polyester material,includes, for example, a number of deeply contoured decorativepictographic surface features which may be abstractions, such as grooves8, beveled regions 10, and widely contoured sections 12. Laminated layer6 may also include pictographic surface features configured to depictanimals, birds, or other decorative designs. Such designs arepictographic in the sense that a bas-relief form is used, together withvariations in surface texture, to represent three dimensional subjectswith widely varying textures and colors. Various outer surfaces 13 oflaminated layer 6 may also have finely-detailed surface textures, toprovide translucence and to otherwise provide visual variations, whichare preferably included among those surface textures conventionallyapplied to decorative glass windows, such as sand blasting, etching, andglue chipping. While laminated layer 6 is preferably transparent, it mayalso be composed primarily of a tinted material to provide a differentvisual effect. The overall shape of window 2 as viewed in the directionof arrow 15, may be rectangular, round, oval or any customized shape.

Laminated layer 6 extends as a single piece across glass sheet 4, exceptfor a narrow peripheral region 16 used in the manufacturing process, aswill be hereafter described, to provide a surface for clamping a mold toreproduce this layer 6. Layer 6 may also include a ledge 17 having auniform thickness extending around its periphery. Decorative window 2can be subsequently mounted within an external frame clamping either orboth peripheral region 16 of glass sheet 4 and/or ledge 17 of laminatedlayer 6. If a variation of the manufacturing process is used, narrowperipheral region 16 can be eliminated.

In any case, after the window 2 is mounted as a decorative element, whenit is viewed in a normal way, substantially in the direction of arrow15, its entire visible front surface will be that of laminated resinlayer 6. Similarly, if it is viewed from the opposite side, in adirection substantially opposite to that of arrow 15, its entire visiblerear surface will be that of glass sheet 4. Thus, any possibledifference between the material of this layer 6 and that of glass sheet4 will not be readily distinguishable. Furthermore, when resin layer 6is carried across glass sheet 4 in this way, a maximum benefit isobtained in combining the mechanical and thermal properties of thematerials of this layer and the glass sheet.

The thickness of the thickest portions of laminated layer 6 ispreferably approximately equal to that of glass sheet 4, since thisrelationship has been subjectively determined to produce a window whichlooks most like a solid glass decorative window. This thickness issufficient to allow deeply grooved and contoured decorative patterns.Also, this relationship provides a good combination of the mechanicaland thermal properties of glass and the plastic resin material.

Referring first to FIG. 2, the manufacturing process for makingdecorative window 2 as a replica of a glass master will now be discussedwith reference to FIGS. 2 through 4. The first step for makingdecorative window 2 as a replica of a glass master is the making of aglass master 18, which has features corresponding to the featuresdesired in the replica. For example, glass master 18 includes grooves8', beveled regions 10', and widely contoured sections 12',corresponding respectively to grooves 8, beveled regions 10 and widelycontoured sections 12 to be reproduced in a replica, such as decorativewindow 2 shown in FIG. 1. Glass master 18 may also include separatetransparent planar surface sections 22, and various other surfaces mayreceive surface texturing by sand blasting, etching, or by strippingaway adhesive attached to a previously sand blasted area. Thesetechniques of contouring and surface texturing are well known to thoseskilled in the art of making decorative glass panels.

All portions of glass master 18 are adhesively mounted on a backingboard 24, along with spacer strips 26 and a peripheral framework 28,which extend around the periphery of glass master 18 regardless of itsshape. Spacer strips 26 are used to determine the overall thickness ofthe laminated resin portion 6 of the replicas 2 which will subsequentlybe reproduced. Small cracks between adjacent pieces of glass are filledby forming plaster fillets 30 in a caulking procedure. Finally, theuntextured portions of glass master 18 are polished to a high gloss, andthe glass master is waxed using a wax product such as Johnson's PasteWax, which can be obtained from S. C. Johnson & Son, Inc. of Racine,Wis.

Referring to FIG. 3, the second step for producing decorative window 2as a replica of glass master 18 is the fabrication of mold 36 forduplicating the surface features of glass master 18. Fabricating mold 36is accomplished by filling a mold producing cavity 32 atop glass master18 and inside peripheral framework 28 with a catalyzed silicone to formmold 36. Peripheral walls 37, formed around the edges of mold 36 extenddownward to the upper surfaces of filler strips 26. The thickness offiller strips 26 determines the overall depth of cavity 32 in mold 36formed by the glass master 18. Adjusting the thickness of filler strips26 can therefore be used to adjust the overall thickness of the resinportion 6 of the replica 2 being subsequently formed, thereby permittingthe use of thick glass plate to facilitate the grinding of deeplycontoured surfaces in glass master 18 without requiring that the resinportion 6 of the replica 2 be correspondingly and unnecessarily thick.

Cavity 32 is then filled with a mixture 38, hereafter described, from acontainer 39 to an intermediate level at which a section of screen wire40 is laid to reinforce the mold 36 being produced. Then, the remainderof the cavity 32 above the screen wire 40 is filled with mixture 38,forming a flat upper surface. Thereafter, mixture 38 is allowed to cureat room temperature for approximately 24 hours to form mold 36. Aftercuring, mold 36 is removed from glass master 18, filler strips 26 andperipheral framework 28.

Mixture 38 includes ten parts HS II RTV Silicone, available from DowCorning Corporation of Midland, Mich., mixed with one part 10:1 ColoredHS II Catalyst, also available from Dow Corning. In addition, a lightoil additive, such as Hoppe's 1003, supplied by Penguin Industries ofCoatsville, Pa. is mixed with a fast curing tin catalyst, such as HS IIRTV Catalyst, also available from Dow Corning. About 30 cubiccentimeters of oil additive and 10 cubic centimeters of fast curingcatalyst is added per pound of silicone mixture. These components aremixed first with each other, and then with the mixture of RTV Siliconeand Colored HS II Catalyst. Before the resulting mixture 38 is pouredinto mold 36, it is placed under vacuum for three to five minutes toremove entrapped air.

The use of the light oil additive makes it unnecessary to apply aconventional mold release agent to the surface of the glass masterbefore the catalyzed silicone is poured. If less than 20 cubiccentimeters of oil is added per pound of silicone mixture, this effectis lost and a conventional mold release agent is needed to prevent thetearing of the mold due to adhesion between the mold and the glass. Ifmore than 40 cubic centimeters of oil is added per pound of siliconemixture, the oil will migrate to the surface of the mold leaving anunacceptable image on the surfaces of replicas formed within the mold.This migration in a mold having too high an oil content occurs overtime; the useful life of such a mold is reduced thereby from acapability of producing over thirty satisfactory replicas to six orless. Thus, adding light oil as an additive in the proper proportioneliminates the need for and associated problems with conventional moldrelease agents, such as, impressions left on the surface of the mold,which in turn leave unacceptable blemishes on the smooth surfaces of thereplicas.

The wax previously applied to the glass master is also a preferred partof this process. If this waxing is not done, a coating of silicone willbe left on the surface of the glass master when the mold is removed. Inthis case, the mold will be suitable for making replicas, but the glassmaster will not be suitable for making additional molds when they arerequired. Using wax in this way does not cause unsatisfactory images tobe left on replicas subsequently made using the mold.

The use of a fast curing tin catalyst hastens the curing process,allowing more rapid mold fabrication. If too much tin catalyst is used,the curing process does not allow an adequate working life for themixture to be properly applied within the mold cavity. Using 10 cubiccentimeters of this catalyst per pound of silicone mixture produces aworking life of about one half hour, which has proven to be adequate forthis purpose.

Referring now to FIG. 4, the third step for making decorative window 2as a replica of glass master 18 is using mold 36 to form a replica. Mold36, after being removed from glass master 18, is inverted from theposition in which it is fabricated, and the flat surface 42 thereof isplaced against a supporting sheet of glass 44 in a fixture 45, withcavity 46, reflecting the shape of glass master 18, directed upward.Fixture 45 is capable of supporting sheet of glass 44 in either aslanted position or in a level position. Fixture 45 may include, forexample, several rows of pegs 52, 54 and 56 upstanding from a table 50.Sheet of glass 44 may be placed on a forward row of pegs 52 and eitheron a lower rear row of pegs 54 or on a higher rear row of pegs 56. Sheetof glass 44 is initially placed in a slanted position, resting on rowsof pegs 52 and 54, so that one end 58 of mold 36 extends upward.

At this point glass sheet 4, which preferably is a tempered sheet ofglass, is prepared for becoming the glass portion 4 of the decorativewindow 2, as previously discussed in reference to FIG. 1. In a preferredversion of this process, this preparation includes coating the side ofglass sheet 4 which is to be attached to the resin layer with anadherent chemical which adheres to both the glass and the resin.Preferably, the adherent chemical permits the resin and glass to adhereto one another by the cross-linkage of polymer chains with the structureof the adherent.

In the preferred process, glass sheet 4 is washed and one surface iscoated with a mixture of alcohol, water and organosilane ester, whichmay be obtained as Type A174 from Union Carbide of Atlanta, Ga. Thepreferred mixture for this purpose is composed of equal volumes ofdeionized water and denatured alcohol to which 0.5 per cent, by volume,of organosilane ester is added. The water and alcohol evaporate, leavinga dried coating of organosilane ester on the surface of glass sheet 4.This coating has been found to function as an adherent when applied inthis manner. This method is superior, in terms of the adhesiveproperties of the lamination subsequently formed, to the use oforganosilane ester simply as a component in the catalyzed resin mixture.

After the adherence coating processing is complete, glass sheet 4 isplaced atop mold 36, against upstanding peripheral walls 37, with thecoated side of glass sheet 4 facing downward into mold cavity 46. Next,spring clamps 62 (only one of which is shown) are placed in spaced apartrelationships around the three sides of mold 36, remote from raised end58. Each spring clamp 62 includes a clamping bracket 64 pivotallymounted on a lower bracket 66 by a rod 68. Each clamping bracket 64includes a clamping tab 70, extending atop glass sheet 4, and an outwardextending clamping handle 72. Similarly, each lower bracket 66 includesa lower tab 74 extending under glass sheet 44 and an outward-extendinglower handle 76. A compression spring 78, extending between clampingbracket 64 and lower bracket 66 outside pivot rod 68, applies clampingforces between tabs 70 and 74, so that the lower surface of glass sheet4 is locally clamped against peripheral walls 37 of mold 36. Springclamps 62 may be manually loosened for installation or removal byapplying manual pressure between the outer surfaces of clamping handle72 and lower handle 76.

A hollow needle-like tube 80, extending from a supply chamber 82 is theninserted into upper end 58 of mold 36 to fill mold cavity 46 with acatalyzed transparent liquid resin 83. A mixture of 97.3 per cent clearpolyester resin, supplied as Product 249A by B.P. Chemicals of Ft.Wright, Ky., 1.0 per cent organosilane ester, supplied as Type A174 byUnion Carbide of Atlanta, Ga., 0.85 per cent methylethylketone peroxide,supplied as Cadox-M-50 by Akzo Chemical of Chicago, Ill., and 0.85 percent heat curing catalyst, supplied as USP-240 by Witco Chemical ofRichmond, Calif. has been found to work well as the catalyzed resin forthis application. Alternately, a tinted plastic resin could be used toobtain a different visual effect in the replica.

The resin curing process is begun by the methylethylketone peroxide andcompleted, as the exothermic reaction raises the temperature of themixture to about 200 degrees F., by the heat curing catalyst. Theorganosilane ester within the mixture, together with the layer of thismaterial which has dried on the surface of the glass sheet 4, promotesthe adhesion of polymers from the resin 83 to the surface of glass sheet4, particularly by the cross-linking of polymer chains within the resinwith organosilane ester adhered to the glass surface. These products maybe properly mixed and dispensed through tube 80 by means of a resintransfer molding machine, such as a Multiflow CVR type, supplied byLiquid Control Corporation of North Canton, Ohio.

This contact between peripheral walls 37 of mold 36 and the underside ofglass sheet 4 prevents the flow of liquid resin into the space betweenthese surfaces, forming narrow peripheral regions 16 of glass sheet 4outside mold cavity 46. If it is necessary to form a resin layerextending to the edges of the glass sheet, alternate sealing means canbe used, such as sealing against these edges.

After a measured amount of liquid resin 83 is introduced into cavity 46in this way, the assembly of mold 36, glass sheets 4 and 44, and springclamps 62 is brought into a level position within fixture 45, with glasssheet 44 resting on pegs 52 and 56, in order to allow the resin 83 toflood the mold completely and evenly. One or more additional springclamps 62 are placed along mold end 58 so that the mold is completelysealed with peripheral walls 37 held against the lower side of glasssheet 4. Any air bubbles, which may have become trapped within theliquid resin 83 during these mixing and pouring processes, are easilyseen by inspection through glass sheet 4 and may be removed by applyinga needle attached to evacuation means (not shown) extending through thesilicone mold 36, which is self-sealing after such small punctures.

This mold assembly is then left in place within fixture 45 to cure. Acomplete cure is achieved at room temperature in one to two hours. Aftercuring, spring clamps 62 are removed, and a replica, consisting of glassplate 4 and a laminated cured resin layer 6 shaped within mold cavity46, is removed from mold 36. Additional replicas of the glass master 18may be produced using mold 36 in the same way again, and additionalmolds may be produced, if required, using glass master 18 in the sameway.

The replica thus formed, which has been previously described asdecorative window 2 in reference to FIG. 1, can be used in a number ofways. For example, this decorative window 2 may be directly used, beingenclosed in a suitable metal framework, with elastomeric strips clampedalong the surfaces of narrow peripheral region 16 of glass plate 4 andagainst ledge 17 of laminated resin layer 6, for use as a shower door.In this application, the window is preferably oriented with laminatedresin layer 6 facing outward, so that the appearance of this layer canbe more readily appreciated, and so that soap and hot water residues maybe more easily removed from an inward surface of glass plate 4. Ascratch-resistant coating can also be applied to the outer surface oflaminated resin layer 6 in accordance with techniques well known in thearts of plastic molding and of producing plastic optical elements, suchas eyeglass lenses.

As shown in FIG. 5, in an alternative embodiment, decorative window 2may be included within a window assembly 84 having a second glass sheet86 fastened to glass sheet 4 in a spaced apart relationship to encloselaminated resin layer 6. Window assembly 84 includes, along each edge, ahollow metal tube 88, of a type which can be obtained as a TrimlineSpacer from the Hygrade Company of New York, N.Y. To form a framework,adjacent tubes 88 are joined at the corners with plastic "L" shapedbrackets (not shown) extending into their hollow centers. Tubes 88,which include inward directed rows of small holes 90, are partly filledwith a desiccating material to prevent the formation of condensedmoisture on surfaces within window assembly 84. The regions between theouter surfaces of tubes 88 and the edges of glass sheets 4 and 86 arefilled with a sealing material 92, such as Polypo, provided by theProduct Research Corporation of Atlanta, Ga., to form a hermetic seal.

One advantage of the configuration of window assembly 84 is that bothexterior sides are glass. This simplifies cleaning, since dirt cannotbecome trapped in the grooves and other features of laminated resinlayer 6, and presents the most scratch resistant surfaces to the outsideon both sides. Furthermore, the "dead air" space, where trapped air isnot circulated, between glass sheets 4 and 86, greatly reduces thetransfer of heat in either direction through the window assembly. Forthese reasons, the configuration of window assembly 84 is particularlysuitable for exterior window openings in buildings.

Referring to FIG. 6, another useful configuration can be obtained, in asecond alternative embodiment, by enclosing a decorative window 2',which is similar to decorative window 2, except for the fact thatlaminated resin layer 6' has been contoured in the molding process toinclude a number of channels 92 in a reticulated pattern. Strips of aframework 94 having a similar pattern are adhesively attached to furthersimulate a structure composed of a number of individual pieces of glassattached by lead strips in the conventional way. Framework 94 mayconsist, for example, of a number of lead alloy strips welded together,of a one-piece lead die casting, or of a one-piece injection moldedthermoplastic part. The pattern formed by the lower surfaces of grooves92 may be flat, providing a uniform thickness between these surfaces andglass sheet 4', or some of these surfaces may be angled relative toglass sheet 4', thereby providing a simulation of separate glasssections installed at various angles. An additional framework 96, havinga pattern opposite to that of framework 94, is adhesively attached tothe opposite surface of glass sheet 4' to increase the effectiveness ofthis simulation. Thus, while a multi-pane window is simulated, theadvantages are retained of having a single laminated layer of resinacross glass sheet 4', except for narrow peripheral regions 16'.

Decorative window 2' may also be surrounded by four strips ofelastomeric spacers 98, having intermediate slots 100, into which endportions of glass sheet 4' extend. Spacers 98 may be obtained as SwiggleStrips from Tremco of Cleveland, Ohio. Spacers of this kind can also beeasily curved to fit around oval or round decorative windows. Afterassembly with additional glass sheets 102 and 104 on each side ofdecorative window 2', heat and pressure are used to melt the surfaces ofspacers 98 adjacent to the glass surfaces, thereby providing adhesionand hermetic sealing.

Thus, in summary, the preferred method for manufacturing the decorativeglass 2 structure begins with the fabrication of a glass master 18 bytechniques well known in the art of making decorative glass windows.Such techniques may include, for example, grinding away portions of arelatively thick piece of glass to form ornamental designs orconventional surface texturing methods may be used to texture the glasssurface. Alternatively, the glass master 18 may consist of an assemblyof various beveled glass segments commonly found on lead crystal glassassemblies. In any case, the glass master 18 is adhesively attached toan underlying support plate 24 with a surrounding frame 28, the glassmaster 18 is polished, where appropriate, to a high gloss, and themaster 18 is waxed.

Next a silicone mold 36 is made to the shape of the glass master 18 bypouring a mixture of silicone and a catalyst over the glass master 18,filling the space inside the surrounding frame 28. After curing, thesilicone mold 36 is pulled away from the glass master 18, and the flatside 42 of the mold 36 is placed atop a waxed surface of amold-supporting sheet of glass 44 with the cavity 46 formed in the moldby the glass master 18 directed upward.

In a preferred embodiment of this process, the composition of thesilicone mold 36 includes a small portion of a light oil additive, whichpermits the separation of the mold from the glass master without damageto the mold. The light oil additive provides a significant moldreleasing advantage over conventional prior art techniques of using moldrelease agents on the surface of the glass master 18, since surfacedefects in the replicas are avoided. Without a clean release, the moldbecomes unusable or only usable for a small number of replications. Nexta sheet of clear glass 4 is cleaned and preferably coated withorganosilane ester to promote adhesion between the resin and the glass.Glass sheet 4 is then clamped in place atop the mold 36, creating acavity 46 identical to the glass master 18.

A liquid catalyzed resin 83, which is preferably a mixture of clearpolyester resin with a catalyst and with organosilane ester, is thenpoured or pumped into cavity 46. The molding form, consisting of mold 36and glass sheets 4 and 44, may be tilted and subsequently leveled to aidthe inward flow of resin 83 and the leveling of resin 83 within thecavity. After curing, the glass sheet 4 atop the mold 36 is separatedfrom the mold 36, leaving decorative replica 2 as glass sheet 4 havinglaminated thereon plastic resin layer 6. Many additional decorativeglass replicas 2 of master 18 can be made using the same mold 36, and,if necessary, additional molds 36 can be made from the master 18 by thesame process.

A number of advantages relative to the prior art are simultaneouslyachieved by the invention described above. While decorative glassreplicas 2 are manufactured for a small fraction of the cost of realdecorative glass products produced by traditional methods, theappearance of the replicas 2 of the instant invention is strikinglysimilar to the real glass products of the prior art. The resin materialsdescribed have excellent optical clarity, with a greenish shading inthick sections very similar to that of glass. Because the resin layer 6of replica 2 can be quite thick, the deeply contoured sections typicalof decorative glass can easily be reproduced. This molding processdescribed above is especially useful for reproducing fine detail, suchas surface texturing, and sharp internal and external corners. Theapplication of the process of this invention results in very goodadhesion between sheet glass 4 and the laminated resin portion 6,preventing delamination due to stresses resulting from thermalexpansion, even when a thick resin layer is applied, and when the windowis in a location having severe temperature swings, such as in anexterior architectural application.

The mechanical and thermal properties of replica 2 are in many wayssuperior to both a traditional decorative glass window or a windowcomposed entirely of a thermoplastic material, such as polycarbonate.Since the resin layer 6 and the glass 4 of replica 2 are tightlyadhered, the toughness of the resin layer 6 reduces the danger that theglass will break in impact situations, while the stiffness of the glassincreases the flexural rigidity of the replica 2 window. Further, therelatively low thermal conductivity of the resin layer 6 reduces theflow of heat through the replica window 2. The thermal insulationproperties can be further improved by the implementation of thealternative embodiments, with additional panes of glass and interveningair spaces.

While the method of this invention produces a replica of a glass masterhaving deeply contoured surfaces and pictographic elements, which may beabstractions or bas-relief representations of various subjects, many ofthe prior art processes produce only wavy surfaces with a degree ofrandomness. An example of such a process is that of U.S. Pat. No.3,848,046 to Machet. While the same general type of plastic resinmaterial may be used to form an article, this Machet process providesonly random wavy nodularity of the surface. Another example of such aprocess is that of U.S. Pat. No. 3,713,958 to McCracken, in which a rodor other tool is used to provide a wavy or irregular surface to a resincoating applied to a glass pane, before the completion of the curingprocess.

While the method of this invention produces a high quality replica ofsurface textures, as well as of deeply contoured surfaces andpictographic elements, each time the mold is used to produce a replica,the implementation of many of the prior art processes requires theregeneration of surface textures each time a part is made. For example,the implementation of U.S. Pat. No. 3,713,958 to McCracken requires theuse of tool to generate this surface for each part, while U.S. Pat. No.4,619,850 to Charlton requires that glue chipping, sand blasting, etc.be done, if they are needed, on each new pane of glass.

With the process of this invention, the glass sheet 4 is a single,continuous piece of glass, even if the resin layer 6 is designed toprovide the appearance of a composite made from a number of individualpieces of glass, such as a traditional leaded glass window. A leadedglass replica 2 may therefore be used in applications where buildingcodes require the use of single-pane windows. Further safety advantagescan be achieved by using tempered glass for the glass sheet 4.

Furthermore, the resin layer 6, with its deeply contoured surfaces, isalso a single continuous piece of material, covering the entire panel,except at most for narrow peripheral regions 16. This contrasts with themethod taught in the alternative construction of U.S. Pat. No. 4,488,919to Butler, where substantially thick sheets of transparent material,which may have faceted or curved outer surfaces, but which are limitedin area to individual design segments to be bounded by externallyapplied lead strips, are attached to a base pane by means of a pressuresensitive adhesive. This also contrasts with a modified version of U.S.Pat. No. 4,619,850 to Charlton, in which a beveled glass segment isadhesively bonded to the glass within an opening in a came network. Thisuse of a continuous contoured layer also contrasts with theconfiguration of U.S. Pat. No. 4,904,513 to De Nicolo, wherein aplurality of beveled flat glass elements are bonded to a backing pane.The use of a continuous resin layer 6 provides mechanical and thermalproperties of continuous material and significantly reducesmanufacturing costs, when compared with the alternative of assembling anumber of individual segments on a pane using a pressure sensitiveadhesive. Furthermore, since the entire front surface of the decorativewindow is composed of the plastic resin material, any differencesbetween this material and glass cannot easily be seen or felt.

Although the invention has been described in preferred forms orembodiments with some degree of particularity, it is understood thatthis disclosure has been made only by way of example, and that numerouschanges in the details of construction, fabrication and use may be madewithout departing from the spirit and scope of the invention.

What is claimed is:
 1. A process of preparing a decorative glass windowhaving a cured resin layer adhered to a glass sheet with a decorativedesign formed in said cured resin layer and remote from said sheet, saidprocess comprising the steps of:coating said glass sheet with anadherent material; clamping a mold to said glass sheet, said mold havinga flat peripheral region and a cavity extending inward within saidperipheral region, said peripheral region being in contact with a saidglass sheet; filling said internal cavity with a catalyzed transparentplastic resin including said adherent material allowing said resin tocure within said internal cavity; and removing said mold from said curedresin and adhered glass sheet.
 2. A decorative glass window prepared bythe process recited in claim 1 wherein said adherent coating adheres tosaid glass and adheres to said resin by the cross-linking of polymersfrom said resin with said adherent.
 3. A decorative glass windowprepared by the process recited in claim 1 wherein said adherentmaterial is organosilane ester.
 4. A decorative glass window prepared bythe process recited in claim 3 wherein said adherent material is coatedon said glass sheet as a mixture of water and alcohol to which about 0.5percent organosilane ester, by volume, has been added.
 5. A decorativeglass window prepared by the process recited in claim 3 wherein saidcatalyzed resin consists essentially of a transparent plastic resin, acatalytic agent for curing said resin and organosilane ester.
 6. Amethod for laminating a plastic resin layer to a glass sheet, to form adecorative glass window, said resin layer having a first side shaped inaccordance with a cavity of a mold and a second side, opposite saidfirst side, laminated to one side of said glass sheet, said methodcomprising the steps of:coating said one side of said glass sheet withorganosilane ester; clamping said one side of said glass sheet againstperipheral surfaces of said mold around said cavity; flooding saidcavity with a catalyzed resin mixture composed essentially of a plasticresin, a catalyst, and organosilane ester; allowing said catalyzed resinmixture to cure within said mold; and removing said glass sheet andcured resin layer adhering thereto from said mold.
 7. The method ofclaim 6 wherein said plastic resin is a clear polyester resin and saidcatalyst is approximately equal parts of methylethylketone peroxide anda heat curing catalyst.
 8. The method of claim 6 wherein said step offlooding includes:orienting said mold in a position with an elevatedside; introducing said mixture at said elevated side; and orienting saidmold to a level position.
 9. A method of making decorative glass using amold having a cavity portion with a decorative surface, the methodcomprising the steps of:affixing the mold to a glass sheet with thecavity portion facing the glass sheet to form a space between the glasssheet and the decorative surface; injecting a curable resin into thespace between the glass sheet and the decorative surface; and removingthe mold from the glass sheet after the resin has cured leaving a layerof cured resin adhered to the glass sheet and having an outer decorativesurface defined by the decorative surface of the mold.
 10. The method ofclaim 9 wherein the decorative surface of the cured resin includes bevelshaped portions.
 11. The method of claim 9 wherein the resin istransparent.
 12. The method of claim 9 wherein the curable resincontains a catalyst and organosilane ester.
 13. The method of claim 12wherein the resin is a polyester and the catalyst includesmethylethylketone peroxide.
 14. The method of claim 12 wherein the resinis a polyester and the catalyst includes a heat curing catalyst.
 15. Themethod of claim 9 further comprising the step of placing the glass sheetand the cured resin layer within a frame to form a window.
 16. Themethod of claim 9 wherein the cured resin layer and the glass sheet areof approximately equal thickness.